SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3578c26b930a17cc01a010cc8268e87dfd98ce3dd093c9414f0574e5a39782ca' 
  AND token = '/2uo9tAYW1UgbPBn4sWdLyCYcQy17pksnE/oRkiNfok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}